Fig. 7. FAAzo-10 enables optical control of [Ca2+]i oscillations in pancreatic islets. [Ca2+]i oscillations were stimulated by a high glucose concentration (11 mM, G11) and monitored in intact mouse islets using the fluorescent [Ca2+]i indicator Fluo-8. (a, b) The application of Gw-9508 (50 μM) caused an increase in the [Ca2+]i oscillation frequency. Displayed as (a) a representative trace from a single islet and (b) the oscillation frequency averaged over multiple islets (n = 6 recordings). (c, d) The application of trans-FAAzo-10 (20 μM) also caused a marked increase in the oscillation frequency. Isomerization to cis-FAAzo-10 with 365 nm irradiation reversed this effect. Results are displayed as (c) a representative trace from a single islet and (d) the average oscillation frequency from multiple islets (n = 5 recordings). (e, f) FAAzo-10 enabled optical control of β-cell [Ca2+]i oscillations at 20 μM, but not at 2.5 μM (n = 4–5 recordings) (representative images cropped to show a single islet; scale bar = 25 μm). (g) FAAzo-10 (20 μM) did not afford a consistent effect on GSIS (3 mM glucose, G3). Gw-9508 (20 μM) also did not affect GSIS (n = 3–8 assays using islets from at least 3 animals) (* denotes significance between G3 and G11). Grey lines are raw traces (to show frequency effects), black lines are smoothed traces (to show amplitude effects). *P < 0.05 and **P < 0.01, ANOVA, with repeated measures as necessary. Error bars were calculated as ±s.e.m.
